Optical arrangement with a spectrally selective element

ABSTRACT

An optical arrangement in the beam path of a light source suitable for fluorescence excitation, preferably in the beam path of a confocal laser scanning microscope, with at least one spectrally selective element ( 4 ) to inject the excitation light ( 3 ) of at least one light source ( 2 ) in the microscope and to extract the excitation light ( 3 ) scattered and reflected on the object or the excitation wavelength from the light ( 13 ) coming from the object ( 10 ) through the detection beam path( 12 ) is characterized for variable configuration with the simplest construction in that excitation light ( 3, 9 ) of different wavelengths can be extracted by the spectrally selective element ( 4 ). Alternatively, an optical arrangement like this is characterized in that the spectrally selective element ( 4 ) can be adjusted to the excitation wavelength to be extracted.

The invention relates to an optical arrangement in the beam path of alight source suitable for fluorescence excitation, preferably in thebeam path of a confocal laser scanning microscope, with at least onespectrally selective element to inject the excitation light of at leastone light source in the microscope and to extract the excitation lightscattered and reflected on the object or the excitation wavelength fromthe light coming from the object through the detection beam path.

In both conventional and confocal laser-scanning microscopy, color beamsplitters with an entirely specialized transmission and reflectioncharacteristic are used in the beam path of a light source suited forfluorescence excitation. This is predominantly a dichroic beam splitter.With an element like this, the fluorescence excitation wavelengthλ_(ill1) or λ_(ill2), λ_(ill3) . . . , λ_(illn) when several lasers areused) is reflected in the illumination beam path in order to excite thefluorescence distribution in the object and then to pass through thebeam path, together with the excitation light dispersed and reflected onthe object, up to the color beam splitter . The excitation light withthe wavelengths λ_(ill1), λ_(ill2), λ_(ill3), . . . , λ_(illn) isreflected back into the laser at the color beam splitter, specificallyout of the detection beam path. The fluorescent light with thewavelengths λ_(fluo1), λ_(fluo2), λ_(fluo3), . . . , λ_(fluon) passesthe color beam splitter and is detected in some cases after furtherspectral subdivision.

Color beam splitters are typically realized by means of an interferencefilter and are purposively attenuated for excitation or for detection,depending on the wavelengths used. At this point it should be noted thataccording to the preceding description of the prior art, awavelength-separable element that splits the light of variouswavelengths on the basis of wavelength and not on the basis ofpolarization is understood as falling under the concept of a dichroit.

In practice the use of color beam splitters is disadvantageous to beginwith in that it involves optical components that are very complex,therefore very expensive, in terms of production. It is alsodisadvantageous that color beam splitters have a fixed wavelengthcharacteristic and therefore cannot be used with flexibility in terms ofthe wavelength of the excitation light. If the wavelength of theexcitation light is changed, the color beam splitters must also bereplaced, for example in an arrangement of several color beam splittersin a filter wheel. However, this is complex and therefore costly,requiring an entirely specialized adjustment of the individual colorbeam splitters.

The use of a color beam splitter is encumbered with the furtherdisadvantage that certain light losses occur due to reflection, inparticular light losses of fluorescent light, which is exactly what isto be detected. The spectral transmission/reflection range is ratherwide for color beam splitters λ_(ill,) ±20 nm) and in no way is ideally“steep”. Consequently, the fluorescent light from this spectral rangecannot be ideally detected.

If color beam splitters are used, the number of lasers that cansimultaneously inject is limited, specifically, for example, to thenumber of color beam splitters which are arranged in and which can becombined for a filter wheel. Typically, a maximum of three lasers isinjected into the beam path. As previously explained, all color beamsplitters, thus also the color beam splitters arranged in a filterwheel, must be adjusted precisely, thereby involving a substantialamount of manipulation. Alternatively, one can use suitable neutral beamsplitters, which efficiently route the fluorescent light together withthe excitation light scattered/reflected on the object. The losses forthe laser injection here are nonetheless considerable.

For documentation of the prior art, merely refer to DE 196 27 568 A1 asan example, which shows an optical arrangement for confocal microscopy.Therefore, in concrete terms this is an arrangement for the simultaneousconfocal lighting of an object plane with a multiplicity of suitabledivergent light points along with accompanying imaging components and amultiplicity of pinholes for confocal contrast-rich imaging in anobservation device, which can be a microscope. The injection of severallight sources is made there by means of a diffractive element. Severaloptical splitter elements or color beam splitters are arranged in thedetection beam path, resulting in a very substantial amount of addedtechnical complexity.

As far as using active optic elements in the beam path of a laserscanning microscope is concerned, refer also to U.S. Pat. No. 4,827,125and U.S. Pat. No. 5,410,371, said documents showing the basic use of anAOD (Acousto-Optical Deflector) and an AOTF (Acousto-Optical TunableFilter), and specifically always with the purpose of deflecting orreducing a beam.

The object of the invention is to design and develop an opticalarrangement in the beam path of a light source suitable for fluorescenceexcitation such that the injection of the excitation light of variousexcitation wavelengths is possible without having to switch or makespecial adjustments to the optical elements used when switching thewavelength of the excitation light. Furthermore, the number of opticalelements required is to be reduced as much as possible. Finally, anideal detection of the fluorescence light should be possible.

The inventive optical arrangement in the beam path of a light sourcesuitable for fluorescence excitation, preferably in the beam path of aconfocal laser scanning microscope, fulfills the object of the inventionby means of the features of the coordinated patent claims 1 and 2. Theseclaims describe an optical arrangement of the type in question that ischaracterized in that by using the spectrally selective element,excitation light of different wavelengths can be extracted or injectedaccordingly. Alternatively, the optical arrangement is characterized inthat the spectrally selective element can be adjusted to the excitationwavelengths to be extracted.

It is recognized according to the invention that the color beam splitterpreviously used in the beam path of a light source suitable forfluorescence excitation, especially in the beam path of a confocal laserscanning microscope, can be replaced by a very unique spectrallyselective element, specifically by a spectrally selective element thatis suitable for extracting or inserting/injecting different wavelengths.This spectrally selective element is used on the one hand to inject theexcitation light of at least one light source in the microscope and onthe other hand to extract the excitation light scattered and reflectedon the object, or the corresponding wavelengths from the light comingfrom the object through the detection beam path. In this respect thespectrally selective element serves a double function, both of thesefunctions being almost mandatorily linked.

As an alternative to the capability of the spectrally selective elementto extract excitation light of different wavelengths, the spectrallyselective element can be adjusted to the particular excitationwavelength to be incorporated or extracted. Also in this respect basedon the previously described double function, a mandatory linking isguaranteed in a simple way, namely that the excitation light can beinjected in the lighting path by using the spectrally selective elementand by extracting exactly the wavelength of the excitation light, namelythe excitation wavelength from the light coming from the object throughthe detection beam path based on the adjustability provided here, sothat the detection light (=fluorescent light) coming from the objectremains for detection.

Advantageously, the spectrally selective element—to favor the previouslydiscussed double function—can be a passive element or component. Thespectrally selective element here can be configured as a transparentoptical grating or as a holographic element. It is also conceivable toconfigure the spectrally selective element as a passive AOD(Acousto-Optical Deflector) or as a passive AOTF (Acousto-OpticalTunable Filter).

In an especially advantageous manner, specifically for the concreterealization of the adjustability of the spectrally selective element tothe excitation wavelength to be extracted, the spectrally selectiveelement can be an active component, for example an element working on anacousto-optical and/or electro-optical basis. In concrete terms thismeans an AOD (Acousto-Optical Deflector) or an AOTF (Acousto-OpticalTunable Filter).

Instead of the color beam splitter that is standard for the prior art,here an active spectrally selective element is used, thus for example anAOD or an AOTF. The purpose of this active component consists ofinjecting the excitation light of the light source or of the laser orlasers λ_(ill1), λ_(ill2), λ_(ill3), . . . , λ_(illn) into theillumination beam path and thus into the microscope in order to thenactivate by beam scanning the fluorescence distribution in the object.For the detection, the fluorescent light coming from the object can passthe active spectrally selective element nearly undisturbed. In theprocess the light scattered or reflected by the object having theexcitation wavelength of the light source or of the laser or lasers fromthe detection beam path is largely reflected out.

For the injection of a light source or of a laser or several lasers withdifferent wavelengths λ_(ill1), λ_(ill2), . . . , λ_(illn), an AOD withcorresponding frequencies v₁, v₂, . . . , v_(n) can be connected,preferably simultaneously, so that the different laser beams, afterpassing through the AOD run coaxially with the optical axis. Regardingthe use of the AOD, it is important that there a frequency v_(n) selectsa wavelength λ_(illn) that is deflected out of the actual beam path. Theangle of deflection φ here is defined by the formula

φ=λ_(illn) v_(n)/2f

f being the expansion speed of the sound wave in the AOD. Thefluorescent light to be detected with a spectral distribution around thewavelengths λ_(fluo1), λ_(fluo2), . . . , λ_(fluon) together with theexcitation light scattered or reflected on the object with thewavelengths λ_(ill1), λ_(ill2), . . . , λ_(illn) then passes through theAOD in the reverse direction. Nevertheless, the excitation light withthe wavelengths λ_(ill1), λ_(ill2), . . . , λ_(illn) is deflected out ofthe detection beam path in the direction of the laser according to thereversibility of the light path based of the specific setting of the AOD(1^(st) order). Thus, the “spectrally remnant” fluorescent light aroundthe wavelengths λ_(fluo1), λ_(fluo2), . . . , λ_(fluon) can be detectedin an improved way, compared with a standard color beam splitter(0-order). In this way the adjustment of the injection of differentlasers can in any event be made more simply than in the prior art (thereusing standard color beam splitters in a filter wheel).

In an additional advantageous way, connecting additional AOTF's couldselectively regulate the individual wavelengths in their power after themerging of the beams.

To insert a laser light source with various wavelengths λ_(fill1),λ_(fill2), . . . , λ_(filln), an AOTF with corresponding frequencies v₁,v₂, . . . , v_(n) can be simultaneously connected so that the differentwavelengths vary in their excitation power and can be optimizedaccording to application. The supply of laser light can be made using afiber optical waveguide.

In any case, the light source or laser is coaxially injected from thedirection of the 1^(st) order of the crystal. The fluorescent light tobe detected with a spectral distribution around the wavelengthsλ_(fluo1), λ_(fluo2), . . . , λ_(fluon), together with the excitationlight with wavelengths λ_(fill1), λ_(fill2), . . . , λ_(filn) scatteredor reflected on the object then pass through the AOTF in the reversedirection. According to the reversibility of the light path, theexcitation light with the wavelengths λ_(fill1), λ_(fill2), . . . ,λ_(filn), are deflected out of the detection path in the direction ofthe light source or laser because of the specific setting of the AOTF.Thus, the “spectrally remnant” fluorescent light around the wavelengthsλ_(fluo1), λ_(fluo2), . . . , λ_(fluon) can be detected (0-order)in—compared to the standard color beam splitter—an improved way.

Using either an AOD or AOTF or even a transparent grating, thefluorescent light, after passing through the particular active element,will spectrally fan itself out based on the dispersion that occurs. Inthis respect, it is advantageous to connect one or more corresponding“inverse” elements downstream so that the undesired spectral fanning outis made to go in reverse again. It is also conceivable to connectadditional optical elements upstream or downstream from the element inquestion (AOD, AOTF or transparent grating) for focusing or forextraction of undesired beam portions. The detection beam reunited inthis way can then be spectrally dissected and depicted on the differentdetectors in a conventional manner using downstream color beamsplitters.

Fundamentally, an arrangement in the sense of a “multi-band detector” isconceivable. Refer to the patent application DE 43 30 347.1-42, thecontent of which is expressly consulted here and in this respect isassumed to be known in the art. The excitation pinhole, this beingidentical to the detection pinhole, is arranged between the scan unitand the AOD, the transparent grating (with several light sources orlasers of several wavelengths) or the AOTF (with one light source or onelaser with various wavelengths). In an advantageous way, thecharacteristic of the crystal here of spectrally fanning out the lightbeam of the 0-order by means of the prism effect is used for detection.The dispersive element of the multi-band detector is combined here withthe color beam splitter into one component so that all additional colorbeam splitters connected downstream from the detection beam path andencumbered with additional losses in the intensity of the fluorescenceare eliminated.

In a very unique way, the previously discussed technique in combinationwith a variable laser light source that is variable in wave length—e.g.dye laser, OPO (optically parameterized oscillator), electron beamcollision light source—can enable exceptionally flexible fluorescencemicroscopy applications. The setting or control of the excitationwavelength can be coupled directly to the drive unit of one of thepreviously described spectrally selective elements so that only thisexcitation wavelength is injected and in turn only this wavelength isextracted from the detection beam path. The coupling or mandatorycoupling of the light source to the beam-splitting element can beaccomplished either manually or automatically or perhaps according apre-determinable specification, whereby this possibility must be adaptedto the current requirement profile. For example, after each scannedfocal plane, the excitation wavelength and the beam splitter can bechanged in a suitable way. In this way multi-colored fluorescenceobjects can be detected. A conversion by lines is also conceivable.

The advantages of the concept according to the invention can besummarized in conjunction with an advantageous embodiment as follows:

The spectrally selective elements are “transparent” for all wavelengthsexcept for the selected excitation wavelengths λ_(ill1), λ_(ill2), . . ., λ_(illn). The “spectral loss” is minimal, since only the selectedspectral range of typically λ_(illn) ±2 nm is deflected by thespectrally selective element. As a result, the spectral range for thedetection is expanded. As a result almost any of the many differentwavelength ranges can be simultaneously injected and used. Thespectrally “lost fluorescent intensity” that is caused by the spectrallyselective elements is less than for standard color beam splitters. Inother words, there are reduced losses in intensity in the range inquestion. The active spectrally selective elements can be flexiblyadjusted so that in principle many light sources or lasers with variouswavelengths can also be injected simultaneously into the microscope.This enables the improved application with multi-color FISH(Fluorescence-In-Situ Hybridization). Consequently, there is still onlya limitation of the spectral splitting of the fluorescent light, forexample, due to “cross-talk”. Standard barrier filters can be completelyomitted so that additional losses of fluorescent light in the detectionare prevented.

Finally, it is also conceivable that another active holographic elementbe connected downstream from the spectrally selective element and thetask of the beam scanner be performed in the process. Both elements canbe combined into a single component.

In principle different light sources can be used as long as they aresuited for fluorescent excitation. The following come to mind asexamples: a white light source, a light source for using an opticparameterized oscillator, an electron beam collision light source or alaser light source, the latter capable of being varied throughwavelength variation. Laser light sources with different wavelengths ora light source comprising several lasers can be used.

There are then different possibilities of configuring and developing thepresent invention in an advantageous way. On this point refer on the onehand to the patent claims subordinate to patent claims 1 and 2, and onthe other hand to the following explanation of preferred embodimentswith reference to the drawings. In connection with the explanation ofthe preferred embodiments of the invention with reference to thedrawings, generally preferred embodiments and developments of theconcept are also explained. Shown in the drawings are:

FIG. 1 in a schematic representation, an optical arrangement of the typein question in the beam path of a confocal laser-scanning microscope fordocumentation of the prior art upon which the invention is based.

FIG. 2 in a schematic representation, a first embodiment,

FIG. 3 in a schematic representation, a second embodiment of aninventive optical arrangement in the beam path of a confocal laserscanning microscope, wherein three lasers with different excitationwavelengths can be injected there,

FIG. 4 in a schematic representation, a third embodiment of an inventiveoptical arrangement in the beam path of a confocal laser scanningmicroscope, wherein the injection of three laser light sources isaccomplished using a transparent grating,

FIG. 5 in schematic representation, enlarged and in a partial view, theillumination beam path and detection beam path, wherein means forconverging the beams are connected downstream of the active spectrallyselective element,

FIG. 6 in schematic representation, enlarged and in a partial view, theillumination beam path and detection beam path, wherein a dispersioncorrection is made there,

FIG. 7 in a schematic representation, the principal mode of operation ofan AOD or AOTF,

FIG. 8 in a schematic representation, an additional embodiment of aninventive optical arrangement, wherein an additional spectral fanningout is performed there in front of a multi-band detector and

FIG. 9 in a schematic representation, the embodiment from FIG. 8,wherein a variable gap is arranged there in the detection beam path.

FIG. 1 documents the prior art and thereby shows a standard opticalarrangement in the beam path of a light source suited for fluorescentexcitation, here an optical arrangement in the beam path of a confocallaser-scanning microscope. The laser scanner 1 here is representedmerely symbolically. In the illustration regarding the prior art, atotal of three lasers 2, which inject with their excitation light 3 byway of spectrally selective elements 4 into the illumination beam path 5of the microscope, are provided as light sources. The spectrallyselective elements 4 in concrete terms are a mirror 6 and a color beamsplitter 7. In any event the excitation light 3 is injected into theillumination beam path 5 and arrives by way of an additional mirror 8 asexcitation light 9 at the laser scanner 1.

The light coming back from the object 10, also represented onlysymbolically—here it is the excitation light 9 scattered and reflectedon the object on the one hand and the fluorescent light 11 sent out fromthe object 10 on the other hand—arrives by way of the mirror 8 at thespectrally selective element 4, here the color beam splitter 7. Fromthere out the excitation light 9 or the excitation wavelength isextracted from the light 13 coming from object 10 by way of thedetection beam path 12 and arrives back at the lasers 2 as returningexcitation light 9. The detection light 14 not deflected by the colorbeam splitter 7 arrives directly at the detector 15.

According to the invention, returning excitation light 3 of variouswavelengths can be extracted by the spectrally selective element 4. Thisis represented in particular in FIG. 4.

Alternatively—in a likewise inventive way—the spectrally selectiveelement 4 can be adjusted to the excitation wavelength to be extracted.This allows the embodiments to be discerned especially well from FIGS.2, 3 and 8, 9.

With the embodiment shown in FIG. 2, only one laser 2 is provided whoseexcitation light 3 can have different wavelengths. In any event, theexcitation light 3 arrives at an AOTF 17, which works as a spectrallyselective element, by way of a mirror 6 and by way of an additionaloptical element, specifically by way of a lens 16. From there out theexcitation light 3 in turn arrives at the laser scanner 1 by way of anadditional optical element—in the embodiment selected here, a lens18—and by way of a mirror 8. Reflected from object 10, the returninglight—reflected excitation light 9 and detection light 11—arrives backin the AOTF 17 by way of the mirror 8 and the lens 18 and there isextracted in part corresponding to the connection of the AOTF 17. Inconcrete terms the detection light or fluorescent light 11 is routedthrough the detection beam path 12 to the detector 15 (0. order). Thereturning excitation light 9, by contrast, is routed back through thelens 16 and the mirror 6 to the laser 2 and thus is extracted from thedetection beam path 12.

The embodiment shown in FIG. 3 behaves similarly, wherein three lasers 2inject their excitation light 3 simultaneously into the illuminationbeam path 5 by way of additional optical elements, in this case lenses16, through an AOD 19, an additional lens connected downstream 18 and amirror 8 in the illumination beam path. From there out the excitationlight 3 arrives at the laser scanner 1 and at object 10.

The light 13 coming from the object, comprises in the aforesaidembodiment fluorescent light 11 and returning excitation light 9,whereby there the AOD 19 routes the returning fluorescent light asdetection light 14 to the detector 15. The returning excitation light 9is extracted and arrives at the lasers 2 in question by way of lenses16.

The embodiment shown in FIG. 4 comprises a transparent grating 20 as thespectrally selective element 4, whereby three lasers 2 inject theirexcitation light 3 into the illumination beam path 5 of the microscopethrough said transparent grating 20. What is essential here in any eventis that the transparent grating 20 extracts the excitation light 9returning from the object 10 from the detection beam path so that thislight arrives back at the lasers 2. The fluorescent light 11 to bedetected arrives at the detector 15 by way of the detection beam path12.

FIG. 5 shows the possibility of a dispersion correction, wherein thelight 13 coming back from the object arrives in the AOTF 17 or AOD 19.There the returning detection light 14 is—mandatorily—spectrally fannedout and is made parallel by means of elements connecteddownstream—AOD/AOTF—and ultimately converges. The spectrally mergeddetection light 14 goes from there to the detector 15 not shown in FIG.5.

With the dispersion correction shown in FIG. 6, the light 13 coming fromthe object is fanned out by means of AOD 17/AOTF 19, whereby the fannedout detection light 14 by means of an additional passive spectrallyselective element 4—AOTF 17 or AOD 19—by way of a lens 21 converts withfield correction and goes through a detection pinhole 22 or through adetection gap to the detector 15.

According to the illustration in FIG. 7, the spectrally selectiveelement 4 is an AOTF 17 or an AOD 19, said elements comprising a specialcrystal with dispersion-free 0-order. This crystal or this spectrallyselective element is activated by or impinged means of a piezoelectricelement 23. FIG. 7 shows especially clearly that the light 13 comingfrom the object is split up in the AOTF 17 or AOD 19, the detectionlight 14 passing unhindered through the crystal as dispersion-free light0-order. The excitation light 9 coming back from the object is bycontrast deflected as 1^(st) order light and back to the lasers notshown here.

FIG. 8 shows a special detection with employment of the spectral fanningout of the spectrally selective element 4, in concrete terms here anAOTF 17. The light 13 coming from object 10 is spectrally split in theAOTF 17, the detection light 14 arriving at a multi-band detector 24 orspectrometer by way of a lens 16 and a mirror 6. The mirror 6 leads toan extension of the reach so that a fanning out of the returningdetection light 14 up to the multiband detector 24 is favored.

The excitation light 9 extracted in the AOTF 17 arrives back to thelaser 2 by way of the lens 16 and the mirror 8.

Finally, FIG. 9 shows in a schematic representation the embodiment fromFIG. 8, whereby there—as a supplement—a variable gap filter 25 isarranged in the detection beam path in front of the multi-band detector24. This gap filter 25 is arranged in the detection beam path directlyin front of the detector 15 and can be positioned within the detectionbeam path. Furthermore, the gap 26 of the gap filter 25 is variable sothat in this respect a spectral selection of the detection light 14 isalso possible.

Regarding additional embodiments of the concept according to theinvention that cannot be inferred from the figures, refer—in order toavoid repetition—to the general part of the description and the mode ofoperation of the concept and the advantageous embodiments describedtherein.

Reference Number List

1 Laser scanner

2 Laser (light source)

3 Excitation light

4 Spectrally selective element

5 Illumination beam path

6 Mirror

7 Color beam splitter

8 Mirror

9 Excitation and detection light

10 Object

11 Fluorescent light (detection light)

12 Detection beam path

13 Light (coming from the object)

14 Detection light (non-deflected detection light)

15 Detector

16 Lens

17 AOTF

18 Lens

19 AOD

20 transparent grating

21 lens (with field correction)

22 detection pinhole

23 piezoelectric element

24 multi-band detector (spectrometer)

25 gap filter (variable)

26 gap (of 25)

What is claimed is:
 1. An optical arrangement in an illumination beampath of at least one light source suitable for fluorescence excitationof an object, said optical arrangement comprising: a spectrallyselective element positioned in said illumination beam path to introducean excitation wavelength from said at least one light source into saidillumination beam path and to extract said excitation wavelength fromlight coming from said object along a detection beam path, wherein saidspectrally selective element is adjustable to change said excitationwavelength to be extracted.
 2. The optical arrangement according toclaim 1, wherein said first spectrally selective element is an activecomponent.
 3. The optical arrangement according to claim 2, wherein saidfirst spectrally selective element works acousto-optically and/orelectro-optically.
 4. The optical arrangement according to claim 3,wherein said first spectrally selective element is an acousto-opticaldeflector (AOD).
 5. The optical arrangement according to claim 4,wherein said at least one light source is a plurality of light sourcesfor supplying a plurality of illumination beams of differentwavelengths, and said AOD is simultaneously connected with correspondingfrequencies so that each of said plurality of illumination beams afterpassing through said AOD is coaxial with an optical axis of saidillumination beam path.
 6. The optical arrangement according to claim 3,wherein said first spectrally selective element is an acousto-opticaltunable filter (AOTF).
 7. The optical arrangement according to claim 6,wherein said at least one light source is a light source that suppliesan excitation wavelength selected from a plurality of differentexcitation wavelengths, and said AOTF is simultaneously connected with aplurality of corresponding frequencies such that said AOTF extracts saidselected excitation wavelength.
 8. The optical arrangement according toclaim 2, wherein said first spectrally selective element is constructedsuch that a spectral fanning out of detection light coming from saidobject along said detection beam path is at least largely prevented. 9.The optical arrangement according to claim 1, further comprising atleast one additional spectrally selective element positioned in saidillumination beam path downstream of said first spectrally selectiveelement for the power-specific regulation of individual wavelengths. 10.The optical arrangement according to claim 9, wherein said additionalspectrally selective element is an AOD.
 11. The optical arrangementaccording to claim 9, wherein said additional spectrally selectiveelement is an AOTF.
 12. The optical arrangement according to claim 2,wherein said first spectrally selective element includes a drive unitfor setting a selected excitation wavelength chosen from said pluralityof different excitation wavelengths, said selected excitation wavelengthbeing mandatorily coupled with said drive unit so that only saidselected excitation wavelength is introduced into said illumination beampath and only said selected excitation wavelength is extracted fromlight coming from said object along said detection beam path.
 13. Theoptical arrangement according to claim i, wherein said at least onelight source is driven in conjunction with said first spectrallyselective element.
 14. The optical arrangement according to claim 13,wherein said at least one light source is automatically driven inconjunction with said first spectrally selective element.
 15. Theoptical arrangement according to claim 13, wherein said at least onelight source and said first spectrally selective element are drivenaccording to a freely definable specification.
 16. The opticalarrangement according to claim 1, wherein at least one additionaloptical element is positioned in either of said illumination beam pathor said detection beam path.
 17. The optical arrangement according toclaim 16, wherein said at least one additional optical element includesan active holographic optical element positioned downstream of saidfirst spectrally selective element and used as a beam scanner.
 18. Theoptical arrangement according to claim 17, wherein said first spectrallyselective element and said holographic optical element are combined intoone functional component.
 19. The optical arrangement according to claim16, wherein said at least one additional optical element includes a beamadjustment means.
 20. The optical arrangement according to claim 19,wherein said beam adjustment means includes a lens.
 21. The opticalarrangement according to claim 19, wherein said beam adjustment meansincludes a prism.
 22. The optical arrangement according to claim 19,wherein said beam adjustment means includes a diaphragm.
 23. The opticalarrangement according to claim 22, wherein said diaphragm is a pinholediaphragm.
 24. The optical arrangement according to claim 22, whereinsaid diaphragm is a slit diaphragm.
 25. The optical arrangementaccording to claim 19, wherein said beam adjustment means includes afilter.
 26. The optical arrangement according to claim 19, wherein saidfilter is a barrier filter.
 27. The optical arrangement according toclaim 25, wherein said filter is arranged directly in front of saiddetector.
 28. The optical arrangement according to claim 19, whereinsaid beam adjustment means includes a focusing means.
 29. The opticalarrangement according to claim 16, wherein said at least one additionaloptical element includes a means for compensation of the spectralfanning out caused by said first spectrally selective element.
 30. Theoptical arrangement according to claim 29, wherein said means forcompensation includes at least one AOTF.
 31. The optical arrangementaccording to claim 30, wherein said at least one AOTF is used as apassive element.
 32. The optical arrangement according to claim 16,wherein said at least one additional optical element includes a colorbeam splitter in said detection beam path for further spectraldissection.
 33. The optical arrangement according to claim 1, furthercomprising reflection means arranged in said detection beam path forextending optical path length to said detector to allow angle expansionof the fanning out of a detection beam.
 34. The optical arrangementaccording to claim 1, further comprising a gap filter arranged in saiddetection beam path in front of said detector.
 35. The opticalarrangement according to claim 34, wherein said gap filter ispositionable relative to said detection beam path.
 36. The opticalarrangement according to claim 34, wherein a gap of said gap filter isvariable.
 37. The optical arrangement according to claim 1, wherein saiddetector is a spectrometer for detection of the spectral fanning out ofa detection beam.
 38. The optical arrangement according to claim 37,wherein said spectrometer is a multi-band detector.
 39. The opticalarrangement according to claim 1, wherein said extracted excitationwavelength is deflected from said detection beam path in a direction ofits light source of origin.
 40. The optical arrangement according toclaim 1, wherein said at least one light source includes a white lightsource.
 41. The optical arrangement according to claim 1, wherein saidat least one light source includes an optically parameterized oscillator(OPO).
 42. The optical arrangement according to claim 1, wherein said atleast one light source includes an electron beam collision light source.43. The optical arrangement according to claim 1, wherein said at leastone light source includes a laser light source.
 44. The opticalarrangement according to claim 43, wherein said laser light source isvariable through variability of the wavelength.
 45. The opticalarrangement according to claim 43, wherein said laser light sourcecomprises a laser with a plurality of different wavelengths.
 46. Theoptical arrangement according to claim 1, wherein said at least onelight source includes a plurality of lasers having differentwavelengths.
 47. The optical arrangement according to claim 43, whereinsaid laser is a dye laser.
 48. The optical arrangement according toclaim 46, wherein said plurality of lasers includes at least one dyelaser.